1. Field of the Invention
Improved hydrogen-forming reaction systems, such as steam/methane reforming and water-gas-shift reaction systems, utilizing a selective hydrogen ion porous metallic foil in direct association with the hydrogen forming reaction system to result in increased hydrogen production under improved hydrogen forming reaction conditions.
2. Description of the Prior Art
Hydrogen forming reaction systems such as steam/methane reforming wherein methane and water are reacted to form carbon dioxide and hydrogen and water-gas-shift reaction systems wherein carbon monoxide is reacted with water to form carbon dioxide and hydrogen, are well known to the art.
Steam/methane reforming is used as a catalytic reaction system for the production of hydrogen. Conventional catalytic systems for steam/methane reforming require catalytic reaction temperatures in the order of 1800.degree. F. followed by rather extensive purification processes including acid gas removal and hydrogen purification to provide hydrogen suitably pure to be used for a feed stock for further processes. Catalytic steam/methane reforming processes currently used are summarized in Kirk-Othmer Encyclopedia of Chemical Technology, Third Edition, Vol. 12, John Wiley & Son, pages 944, 950-951.
The water-gas-shift reaction is frequently used following gasification of naturally occurring carbonaceous materials, such as coal, peat, oil shale and the like, wherein the product gas temperatures must be lowered to about 750.degree. F. to drive the water-gas-shift reaction. A review of current applications and processes for the water-gas-shift reactions is given in Kirk-Othmer Encyclopedia of Chemical Technology, Third Edition, Vol. 12, John Wiley & Sons, pages 945, 951-952.
The use of metallic foils for separating gaseous mixtures, particularly hydrogen, has been known to the art as a separation or purification technique. For example, U.S. Pat. No. 1,174,631 teaches hydrogen separation from a gaseous mixture using a thin sheet or film of platinum or palladium at a temperature of preferably above about 1470.degree. F. U.S. Pat. No. 2,773,561 teaches purification of hydrogen by permeation through a thin film of silver-palladium under a pressure differential between opposite sides of the film.
The prior art patents teach use of metallic foils for separating hydrogen from gaseous product mixtures, but do not suggest the use of metallic foils for withdrawal of hydrogen in hydrogen forming reaction systems. The parent application to this application, to issue as U.S. Pat. No. 4,702,973, teaches use of a hydrogen ion porous metallic foil to provide a dual compartment anode structure for use in molten carbonates fuel cells. In the prior patent application, the hydrogen ion porous metallic foil separates an anode reaction gas compartment from an anode fuel compartment through which hydrogen fuel contaminated with materials detrimental to the electrochemical reaction or the molten carbonates electrolyte may be maintained separated from the reaction gas compartment. The dual compartment anode configuration makes internal reforming of fuels practical in a fuel cell since a reforming catalyst may be placed in the fuel gas compartment and maintained in separated relation from the electrochemical reaction and molten carbonates electrolyte, thereby prevent poisoning of the reforming catalyst by the molten carbonates electrolyte and provide enhancement of the reforming reaction by withdrawal of formed hydrogen directly from the fuel reforming region.